ORIGINAL: savagescout
All rifles are different some take longer than others, some shoot awesome right from the getgo.I would not give up on a new rifle untill you have 150-200 rds though it.
Whether or not a rifle has to be "broken in", and if so, HOW, is a big question. A lot depends on the barrel, what you plan to use the rifle for, and what your accuracy standards are. For example, for most hunting rifles (deer & larger) I am satisfied with 5-shot groups of 1.25" or smaller. If I can get such performance from a rifl right out of the box with the ammo I am going to use in it (handloads,of course), I will clean it and that's that!
For a varmint rifle, I want 0.5 MOA with the correct ammo. If the rifle will not shoot that well, I will attempt to find out why, and fix it. This fix may or may not include some arcane ritual performed on the barrel. Shooting & cleaning, shooting & cleaning, etc., may work. So might urinating down the barrel at midnight on the full phase of a blue moon, to drive out the evil spirits! This works especially well with flintlocks-Jaegers,Long Rifles and Hawkens..........
Actually, when a rifle fails to group well, 99 times out of 100, the problem stems from poor bedding of the stock & barreled action somewhere............. NOT from how it was or was not "broken in"!